Seismic fracture analysis of concrete gravity dams based on nonlinear fracture mechanics

In this paper, a numerical scheme based on nonlinear crack band theory is presented to study the 2D seismic fracture behaviour of concrete gravity dams. A mesh size of the finite elements close to the characteristic size of the crack band of concrete material is adopted, so that the strain softening behaviour of the concrete can be properly taken into account. Also, a technique of finite element (FE) remesh at the crack front is presented by changing the element edge pairs of the cracking element candidate to be parallel with the principal tensile stresses, in order to better accommodate the crack extension. The procedure is verified using test results for a notched beam and then applied to the seismic-fracture analysis of the Koyna dam in India as a demonstration of prototype application. In addition, several features of the present analysis influencing the predicted concrete fracture process are also studied; these comprise the magnitude of the fracture energy G(f), the form of the strain-softening relation and the introduction of FE remesh at the crack front. (C) 2000 Elsevier Science Ltd. All rights reserved.